Specific chemicals are widely used in flavour compositions to provide a particular element in the total flavour appreciated by the user. One example of such a chemical is gamma-decalactone which is the lactone of gamma-hydroxydecanoic acid. An example of the use of this material as a flavour is given in UK 743845 (Unilever); this component is also used in perfume compositions. There is a general requirement to produce this component in an efficient procedure.